The light emitting diode is a device which emits light when current is applied and electrons and holes meet at the P-N semiconductor junction (P-N junction), and it is generally manufactured in a structure of a module on which the light emitting diode is mounted. A light emitting diode module is configured to be mounted on a printed circuit board (PCB) and operate to emit light when it receives current from an electrode formed on the printed circuit board.
In such a light emitting diode module, heat generated by the light emitting diode directly affects light emitting performance and lifespan of the light emitting diode module. If the heat generated by the light emitting diode stays in the light emitting diode for a long time, dislocation and mismatch occur in the crystal structure configuring the light emitting diode, and this will act as a cause for reducing the lifespan of the light emitting diode module.
Accordingly, techniques for accelerating dissipation of heat generated by a light emitting diode are proposed. For example, a light emitting diode package having a ceramic substrate combined with a light emitting diode chip can be mounted on a circuit substrate, or a light emitting diode chip can be mounted in a Chip On Board (COB) method after an aluminum oxide (Al2O3) insulation layer is formed by performing anodization on an aluminum substrate.
Expensive Nitride-based aluminum nitride (AlN) may be used for the ceramic substrate applied to the light emitting diode package. In addition, thickness of the ceramic substrate should be 400 μm or more to secure durability. Accordingly, the unit price is increased if the ceramic substrate is applied to the light emitting diode package, and there is a limit in lowering thermal resistance of the vertical direction.
In the case of the COB method using an aluminum oxide insulation layer, the unit price can be lowered since the expensive ceramic substrate is omitted. However, it is difficult to implement high heat dissipation performance since characteristics of high thermal resistance and low withstand voltage are shown compared with a case of applying a ceramic substrate, and it is difficult to apply the light emitting diode module to a high power product such as a head lamp.